[lancerlover]

GDI-GASOLINE DIRECT INJECTION

In GDI unlike the coventional MPFI engine a mpfi is placed directly on a cylinder of a SI engine.
This drastically improves the fuel efficiency and performance of the engine.
fo eg: a zen with GDI would give a mileage of around 30kmpl.

The only considerations are the quality of fuel(highly filtered and high octane)+the high initial cost of the injector.

This technology is patented by mitsubishi and is currently used in some of their cars sold in the U.S and JAPAN.

[Shan2nu]

30kmpl is impressive. So when are they getting it here.

Shan2nu

[johnjacob]

Originally Posted by lancerlover

GDI-GASOLINE DIRECT INJECTION

In GDI unlike the coventional MPFI engine a mpfi is placed directly on a cylinder of a SI engine.
This drastically improves the fuel efficiency and performance of the engine.
fo eg: a zen with GDI would give a mileage of around 30kmpl.

The only considerations are the quality of fuel(highly filtered and high octane)+the high initial cost of the injector.

This technology is patented by mitsubishi and is currently used in some of their cars sold in the U.S and JAPAN.

It's not just Mitsubishi. Audi (and maybe VW?) have their own version of GDI, and Mercedes and some other manufacturer's have licensed Mitsu's GDI technology (if I remember correctly).

[lancerlover]

with the quality of fuel available here and the psychi of the indian automobile manufacturers it may take anywhere between 20-30 years we see this technology in india.

maybe different compnies hav different versions but as such GDI technology has been patented by mitsubishi and they are already selling cars with GDI.

[Shan2nu]

they are already selling cars with GDI.

Can you name some cars? Do the evos have it?

Shan2nu

[lancerlover]

yup the latest lancers + evo8 sold in the U.S and Japan hav engines based on this tecnology

[Kinetik]

audi calls it FSI , and its been selling it since a while now

[Deeps]

This is nothing new. Mitsubishi have been using GDI engines for a few years now!!

[shonak159]

Mod Note : Please use the EDIT or MULTI-QUOTE buttons instead of typing one post after another!

I am new to this forum

Need some details on GDi tech, I know minituarisation of the engine is the in thing as one can see in case of 1.4 Ltrs under the New Jetta Hood. but beyound turbocharging is there anything more in Hyudai's GDI engine and how does it compare with TSI, FSI,

Yes I agree with Deeps, basis my little understanding of Mitsubishi engine, its kind of outdated, thanks to the startefied injection approach.

[sarthakgupta]

GDI Issues
Ask An Engineer: GDI Problems In A Nutshell | The Truth About Cars


“Ask an Engineer” is hosted by Andrew Bell, a mechanical engineer and car enthusiast. Andrew has his MASc in Mechanical Engineering from the University of Toronto, and has worked on Formula SAE teams, as well as alternative fuel technologies in Denmark and Canada. Andrew’s column will explore engineering topics in the most accessible manner possible.

Even though every other car nowadays seems to offer gasoline direct injection (GDI), Mercedes-Benz was the first to exploit this technology in the 1955 300SL. But it wasn’t until the mid-1990’s that other automakers started to use GDI in mass produced vehicles. GDI promises marginal increases in fuel economy (3% reduction in BSFC ) but its real benefits include reduced cold start/low load emissions and higher power outputs. While the technology offers engineers incredible flexibility from an engine design perspective, it is not without faults. As with any new technology it is important to understand both the positives and negatives before you choose, say a compact car with GDI or one regular fuel injection. If you want to keep your car for a long period of time, the long-term reliability of a GDI engine is an important factor.

The effect of increased percentages of ethanol on injector longevity:
The percentage of ethanol in gasoline at the pumps is steadily increasing. Ethanol has a tendency to increase the corrosion rate of the various metals used in an engine. Add this to the elevated fuel pressure and the fact the injector is directly exposed to in-cylinder combustion events, and you have a recipe for a recall. Furthermore, these injectors are very sensitive to fuel quality due to outrageously tight tolerances. It is very important to use high quality fuels and keep the filters clean.

Higher pressures in general:
GDI requires significantly higher fuel inlet pressures than port injection. This puts a great deal of strain on every piece of the fuel delivery chain. This is not a problem on a new engine. 50,000 miles down the road, and it may be. Manufacturers have been relatively proactive in this department by specifying robust, stainless steel fuel lines and connections. That hasn’t stopped fuel pump recalls from already occurring.

Carbon buildup on intake valves:
This is the big problem with most current GDI engines. Due to modern unburned hydrocarbon (UHC) regulations, vapors from the crankcase are usually vented into the intake stream in order to prevent oil droplets from escaping through the exhaust. In a port injection engine, these droplets are ‘washed off’ the neck of the intake valve by a relatively constant stream of gasoline droplets. In a GDI engine, the gasoline doesn’t touch intake side of the valve. As a result, the droplets have a tendency to bake onto the valve and significantly reduce performance. To add to this effect, many advanced GDI engines also include exhaust gas recirculation in order to lean out the combustion mixture and reduce in-cylinder temperatures for certain combustion modes (reducing NOx emissions). Since GDI combustion has the ability to produce far more soot than premixed combustion (port injection), the problem is magnified.

Even more alarming is that these deposits can dislodge and damage other downstream components (turbochargers, catalytic converters, etc.). Manufacturers have added systems to capture these oil droplets and particulates, but no system is 100% effective. As a result, there are many disappointed early adopters with large repair bills. Even diesel engines haven’t been immune to these issues.

The reason these issues have slipped through to production is that they won’t show up in a 500,000 mile torture test. These types of issues will appear after years of short trips (preventing the engine from reaching operating temperature), bad batches of fuel, etc. As we approach the efficiency limits of the internal combustion engine, the engines themselves (and associated support systems) have become more complex. As with the transition from carburetors to electronic fuel injection, there will be some overlap between relatively bombproof port injected engines and the unproven, first-generation GDI engines.

[TaurusAl]

The Diagram makes it easy to understand.

Knowing the major advantages of a GDI engine are increased fuel efficiency and high power output, I'm sure it is the next big thing.

[shonak159]

Thanks Sarthak and Tarus AI , whilst Sarthak seems to have decided,to reflect on GDi's negatives and rightly so, however, I think, companies won't have invested so much money on a tech without knowing its downside. Chances are that ven accelerated tests might not reveal all negatives, but there still has to be a positive story. Tarus's schematic drwaing is quite good and I must admit during one of my searches came across a detailed noted on Hyudnai Theha II Gdi engine. Posting the link here for you guys also to ahve a look and comment
Street new details